US6990132B2 - Laser diode with metal-oxide upper cladding layer - Google Patents

Laser diode with metal-oxide upper cladding layer Download PDF

Info

Publication number
US6990132B2
US6990132B2 US10/394,560 US39456003A US6990132B2 US 6990132 B2 US6990132 B2 US 6990132B2 US 39456003 A US39456003 A US 39456003A US 6990132 B2 US6990132 B2 US 6990132B2
Authority
US
United States
Prior art keywords
oxide
layer
laser diode
ito
metal
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Active, expires
Application number
US10/394,560
Other versions
US20040184497A1 (en
Inventor
Michael A. Kneissl
Linda T. Romano
Christian G. Van de Walle
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Xerox Corp
Original Assignee
Xerox Corp
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Xerox Corp filed Critical Xerox Corp
Assigned to XEROX CORPORATION reassignment XEROX CORPORATION ASSIGNMENT OF ASSIGNORS INTEREST (SEE DOCUMENT FOR DETAILS). Assignors: ROMANO, LINDA T., KNEISSL, MICHAEL A., VAN DE WALLE, CHRISTIAN G.
Priority to US10/394,560 priority Critical patent/US6990132B2/en
Assigned to JPMORGAN CHASE BANK, AS COLLATERAL AGENT reassignment JPMORGAN CHASE BANK, AS COLLATERAL AGENT SECURITY AGREEMENT Assignors: XEROX CORPORATION
Publication of US20040184497A1 publication Critical patent/US20040184497A1/en
Publication of US6990132B2 publication Critical patent/US6990132B2/en
Application granted granted Critical
Assigned to DARPA reassignment DARPA CONFIRMATORY LICENSE Assignors: XEROX CORPORATION
Active legal-status Critical Current
Adjusted expiration legal-status Critical

Links

Images

Classifications

    • BPERFORMING OPERATIONS; TRANSPORTING
    • B82NANOTECHNOLOGY
    • B82YSPECIFIC USES OR APPLICATIONS OF NANOSTRUCTURES; MEASUREMENT OR ANALYSIS OF NANOSTRUCTURES; MANUFACTURE OR TREATMENT OF NANOSTRUCTURES
    • B82Y20/00Nanooptics, e.g. quantum optics or photonic crystals
    • HELECTRICITY
    • H01BASIC ELECTRIC ELEMENTS
    • H01SDEVICES USING THE PROCESS OF LIGHT AMPLIFICATION BY STIMULATED EMISSION OF RADIATION [LASER] TO AMPLIFY OR GENERATE LIGHT; DEVICES USING STIMULATED EMISSION OF ELECTROMAGNETIC RADIATION IN WAVE RANGES OTHER THAN OPTICAL
    • H01S5/00Semiconductor lasers
    • H01S5/20Structure or shape of the semiconductor body to guide the optical wave ; Confining structures perpendicular to the optical axis, e.g. index or gain guiding, stripe geometry, broad area lasers, gain tailoring, transverse or lateral reflectors, special cladding structures, MQW barrier reflection layers
    • H01S5/22Structure or shape of the semiconductor body to guide the optical wave ; Confining structures perpendicular to the optical axis, e.g. index or gain guiding, stripe geometry, broad area lasers, gain tailoring, transverse or lateral reflectors, special cladding structures, MQW barrier reflection layers having a ridge or stripe structure
    • HELECTRICITY
    • H01BASIC ELECTRIC ELEMENTS
    • H01SDEVICES USING THE PROCESS OF LIGHT AMPLIFICATION BY STIMULATED EMISSION OF RADIATION [LASER] TO AMPLIFY OR GENERATE LIGHT; DEVICES USING STIMULATED EMISSION OF ELECTROMAGNETIC RADIATION IN WAVE RANGES OTHER THAN OPTICAL
    • H01S5/00Semiconductor lasers
    • H01S5/20Structure or shape of the semiconductor body to guide the optical wave ; Confining structures perpendicular to the optical axis, e.g. index or gain guiding, stripe geometry, broad area lasers, gain tailoring, transverse or lateral reflectors, special cladding structures, MQW barrier reflection layers
    • H01S5/2004Confining in the direction perpendicular to the layer structure
    • HELECTRICITY
    • H01BASIC ELECTRIC ELEMENTS
    • H01SDEVICES USING THE PROCESS OF LIGHT AMPLIFICATION BY STIMULATED EMISSION OF RADIATION [LASER] TO AMPLIFY OR GENERATE LIGHT; DEVICES USING STIMULATED EMISSION OF ELECTROMAGNETIC RADIATION IN WAVE RANGES OTHER THAN OPTICAL
    • H01S5/00Semiconductor lasers
    • H01S5/30Structure or shape of the active region; Materials used for the active region
    • H01S5/32Structure or shape of the active region; Materials used for the active region comprising PN junctions, e.g. hetero- or double- heterostructures
    • H01S5/3211Structure or shape of the active region; Materials used for the active region comprising PN junctions, e.g. hetero- or double- heterostructures characterised by special cladding layers, e.g. details on band-discontinuities
    • H01S5/3214Structure or shape of the active region; Materials used for the active region comprising PN junctions, e.g. hetero- or double- heterostructures characterised by special cladding layers, e.g. details on band-discontinuities comprising materials from other groups of the periodic system than the materials of the active layer, e.g. ZnSe claddings and GaAs active layer
    • HELECTRICITY
    • H01BASIC ELECTRIC ELEMENTS
    • H01SDEVICES USING THE PROCESS OF LIGHT AMPLIFICATION BY STIMULATED EMISSION OF RADIATION [LASER] TO AMPLIFY OR GENERATE LIGHT; DEVICES USING STIMULATED EMISSION OF ELECTROMAGNETIC RADIATION IN WAVE RANGES OTHER THAN OPTICAL
    • H01S5/00Semiconductor lasers
    • H01S5/30Structure or shape of the active region; Materials used for the active region
    • H01S5/34Structure or shape of the active region; Materials used for the active region comprising quantum well or superlattice structures, e.g. single quantum well lasers [SQW-lasers], multiple quantum well lasers [MQW-lasers] or graded index separate confinement heterostructure lasers [GRINSCH-lasers]
    • H01S5/343Structure or shape of the active region; Materials used for the active region comprising quantum well or superlattice structures, e.g. single quantum well lasers [SQW-lasers], multiple quantum well lasers [MQW-lasers] or graded index separate confinement heterostructure lasers [GRINSCH-lasers] in AIIIBV compounds, e.g. AlGaAs-laser, InP-based laser
    • HELECTRICITY
    • H01BASIC ELECTRIC ELEMENTS
    • H01SDEVICES USING THE PROCESS OF LIGHT AMPLIFICATION BY STIMULATED EMISSION OF RADIATION [LASER] TO AMPLIFY OR GENERATE LIGHT; DEVICES USING STIMULATED EMISSION OF ELECTROMAGNETIC RADIATION IN WAVE RANGES OTHER THAN OPTICAL
    • H01S5/00Semiconductor lasers
    • H01S5/30Structure or shape of the active region; Materials used for the active region
    • H01S5/34Structure or shape of the active region; Materials used for the active region comprising quantum well or superlattice structures, e.g. single quantum well lasers [SQW-lasers], multiple quantum well lasers [MQW-lasers] or graded index separate confinement heterostructure lasers [GRINSCH-lasers]
    • H01S5/343Structure or shape of the active region; Materials used for the active region comprising quantum well or superlattice structures, e.g. single quantum well lasers [SQW-lasers], multiple quantum well lasers [MQW-lasers] or graded index separate confinement heterostructure lasers [GRINSCH-lasers] in AIIIBV compounds, e.g. AlGaAs-laser, InP-based laser
    • H01S5/34333Structure or shape of the active region; Materials used for the active region comprising quantum well or superlattice structures, e.g. single quantum well lasers [SQW-lasers], multiple quantum well lasers [MQW-lasers] or graded index separate confinement heterostructure lasers [GRINSCH-lasers] in AIIIBV compounds, e.g. AlGaAs-laser, InP-based laser with a well layer based on Ga(In)N or Ga(In)P, e.g. blue laser

Abstract

A nitride-based laser diode structure utilizing a metal-oxide (e.g., Indium-Tin-Oxide (ITO) or Zinc-Oxide (ZnO)) in place of p-doped AlGaN to form the upper cladding layer. An InGaN laser diode structure utilizes ITO upper cladding structure, with an SiO2 isolation structure formed on opposite sides of the ITO upper cladding structure to provide a lateral index step that is large enough to enable lateral single-mode operation. The lateral index step is further increased by slightly etching the GaN:Mg waveguide layer below the SiO2 isolation structure. An optional p-type current barrier layer (e.g., AlGaN:Mg having a thickness of approximately 20 nm) is formed between the InGaN-MQW region and a p-GaN upper waveguide layer to impede electron leakage from the InGaN-MQW region.

Description

FIELD OF THE INVENTION
This invention relates to laser diodes, and more particularly to nitride-based laser diode structures.
BACKGROUND OF THE INVENTION
Laser diodes are used in many laser applications, such as in laser printing, optical data storage, long-haul fiber communication, spectroscopy, metrology, barcode scanners, and fiber amplifier pump sources. Laser diode structures generally include a central waveguide/quantum well “active” region flanked by upper and lower cladding layers. This configuration is also known as separate confinement heterostructure (SCH). Because of its high refractive index, light is confined to this active region “core” of the structure, where optical gain is produced. The upper and lower cladding layers are formed from material having a lower refractive index than the core, and serve to contain the optical mode. This arrangement guides the optical mode along the active region core, creating a laser light beam that is emitted from a face of the structure.
FIG. 3 is a simplified perspective view depicting a conventional Indium-Gallium-Nitride (InGaN) multi-quantum-well (MQW) laser diode 50, which is exemplary of the type of nitride-based laser diode specifically addressed by the present invention. Referring to the lower portion of FIG. 3, laser diode 50 includes an n-doped layer 62 (e.g., Silicon-doped Gallium-Nitride (GaN:Si)) formed on a substrate 60 (e.g., Sapphire (Al2O3), Silicon-Carbide (SiC), Aluminum-Nitride (AlN), or Gallium-Nitride (GaN)). An n-electrode 64 (e.g., a Titanium-Aluminum (Ti/Al) or Titanium-Gold (Ti/Au) bilayer) and an n-doped cladding layer 66 (e.g., Si-doped Aluminum-Gallium-Nitride (AlGaN:Si)) are formed on n-doped layer 62. A stack is formed on n-doped cladding layer 66 that includes an n-doped waveguide layer 68 (e.g., GaN:Si), a multiple quantum well (MQW) region 70 including multiple (e.g., three) InGaN quantum wells separated by GaN barrier layers, a p-doped waveguide layer 74 (e.g., GaN:Mg), a p-doped cladding layer 76 (e.g., AlGaN:Mg), a second p-doped contact layer 78 (e.g., GaN:Mg), and a p-electrode 80 (e.g., a Ni/Au bilayer). During the operation of InGaN MQW laser diode 50, a suitable voltage potential is applied to n-electrode 64 and p-electrode 80. The respective n-type and p-type materials inject electrons and holes from these electrodes to the p-n junction provided by MQW region 70, which produces a highly coherent (in this case blue-violet) laser beam LB that is emitted from an area 51 located on a face of laser diode 50. In general, the purpose of the waveguide and cladding layers is to confine the optical mode to a central (core) region of MQW region 70 associated with area 51. This is achieved by forming waveguide layers 68 and 74 from materials having relatively high refractive indexes (although lower than that of MQW region 70), and cladding layers 66 and 76 from materials having relatively low refractive indexes. For several reasons, cladding layers 66 and 76 are formed by adding Al to the material used to form waveguide layers 68 and 74, along with an appropriate dopant (e.g., Si or Mg).
It is critical that laser diodes be precisely formed and made from materials of excellent structural and optoelectronic quality in order to optimize the emitted laser beam. Structural defects (such as dislocations or cracks) or impurities can seriously degrade the luminescence efficiency of the semiconductor materials. In addition, the thickness and shape of the various layers are important to optimize the emitted laser beam.
A problem associated with the use of AlGaN:Mg to produce upper cladding layer 76 of InGaN laser diode 50 (FIG. 3) is that both the thickness and Al concentration are limited by cracking, which then limits the refractive index difference between upper cladding layer 76 and waveguide layer 74 and the active region formed by MQW region 70, and consequently limits the resulting optical confinement. In addition, it is difficult to achieve a high hole concentration in AlGaN alloys because the ionization energy of Mg acceptors increases with increasing Al content. Therefore, Mg doped AlGaN cladding layers increase the series resistance, and ultimately produce undesirable heating of InGaN laser diode 50 during operation. Furthermore, reliable control of the lateral optical mode has proven to be difficult in conventional InGaN laser devices, where typically a ridge-waveguide structure is employed for lateral confinement of the optical mode. A lateral index step is achieved by dry-etching upper AlGaN:Mg cladding layer 76. Because there is no reliable selective etch process known for AlGaN, the etch depth and the resulting index step are difficult to control.
FIGS. 4(A), and 4(B) are graphs depicting modeling data associated with conventional nitride laser diode structure 50 having a ten-InGaN/GaN MQW region 70 and an upper cladding layer 76 comprising Al0.08Ga0.92N:Mg. FIG. 4(A) is a graph showing calculated confinement factors Γ depending on the AlGaN:Mg cladding layer thickness, and indicates a confinement factor Γ of the optical mode is expected to be around 0.08. FIG. 4(B) is a graph showing calculated metal absorption loss for a conventional 10 InGaN/GaN-MQW laser diode structure for different top p-electrode metal layers as a variation of the AlGaN:Mg cladding layer thickness. As indicated, the absorption loss from the top p-metal layer in such a structure depends greatly on the thickness of the AlGaN:Mg cladding layer. In order to achieve reasonable low loss values (˜1 cm−1), a cladding layer thickness in the range of 400–500 nm is necessary. Further, these loss values are only a lower estimate, not taking into account the losses due to surface roughness (e.g., induced by the metal alloy fabrication process) or metal penetrating into the (Al)GaN layers. Therefore, in order to improve the optical confinement and reduce absorption loss, the AlGaN:Mg layer ideally should be kept as thick as possible. However, as set forth above, AlGaN:Mg contributes significantly to the series resistance of the device, and also has to be kept thin enough in order to avoid cracking, which degrades the optoelectronic quality of the laser diode. An AlGaN:Mg free device structure would therefore be beneficial in order to overcome these two problems.
What is needed is an index guided single-mode laser diode structure that does not include a p-AlGaN cladding layer, while still maintaining the same optical confinement factor and avoiding significant absorption loss in the p-metal. In addition, the series resistance in the laser diode should be largely reduced. The laser diode structure must also provide a strong (index-guided) lateral confinement, which could be beneficial in order to achieve stable single-mode operation of the laser diode devices.
SUMMARY OF THE INVENTION
The present invention is directed to a laser diode structure that includes an upper cladding layer formed from a conductive metal-oxide (e.g., Indium-Tin-Oxide (ITO) or Aluminum-doped Zinc-Oxide (ZnO)), thereby providing several advantages over conventional ridge-waveguide laser diode structures having conventionally-formed upper cladding layers. The use of a metal-oxide upper cladding layer is shown to be beneficial in nitride-based (e.g., InGaN) laser diode structures that conventionally utilize Aluminum-Gallium-Nitride doped with Magnesium (i.e., AlGaN:Mg) to form the p-doped upper cladding layer (however, the use of metal-oxide upper cladding layers may benefit other types of laser diode structures as well). For example, in nitride-based laser diode structures, the metal-oxide cladding layer provides better control over the lateral index step and lateral mode profile than that provided by conventional cladding materials such as AlGaN:Mg. Second, the conductive metal-oxide cladding layer provides less series resistance than conventional cladding materials such as AlGaN:Mg. Third, the metal-oxide cladding layer provides enhanced transverse optical confinement and modal gain when compared to that of conventional AlGaN-based laser diode structures. Fourth, the use of metal-oxide to form the upper cladding layer greatly simplifies the fabrication process because it can be selectively wet etched, whereas AlGaN:Mg must be carefully dry etched to prevent damage to the underlying GaN:Mg waveguide layer typically utilized in AlGaN-based laser diode structures. This simplification of the fabrication process contributes to lower manufacturing costs than those associated with conventional AlGaN-based laser diode structures.
In accordance with a specific embodiment of the present invention, an AlGaN-based laser diode structure includes an n-type lower cladding layer (e.g., AlGaN:Si), an n-type lower waveguide layer (e.g., GaN:Si) formed on the lower cladding layer, an InGaN-based multiple quantum well (InGaN-MQW) region formed on the lower waveguide layer, a p-type upper waveguide layer (e.g., GaN:Mg) formed over the InGaN-MQW, an ITO upper cladding layer formed on the upper waveguide layer, and an electrode (e.g., TiAu) formed on the ITO upper cladding layer. ITO has a much higher conductivity than AlGaN:Mg, and therefore its use as a cladding material reduces the operating voltages when compared with conventional nitride-based laser diode structures having thick AlGaN:Mg cladding layers. In addition, because ITO has a refractive index that is substantially lower than GaN, ITO provides a sufficiently large refractive index step to serve as the upper cladding layer in laser diode structures utilizing p-GaN to form the upper waveguide layer. Further, calculations show that the total optical confinement factor for laser diodes structures using ITO upper cladding layers is greater than the confinement factor for conventional devices with p-AlGaN upper cladding layers, and should therefore result in enhanced modal gain and lower threshold current densities. Moreover, utilizing ITO to form the upper cladding layer greatly simplifies production by allowing selective wet or dry etching of the ITO (i.e., without etching the underlying GaN waveguide layer).
In accordance with another aspect of the specific embodiment, SiO2 isolation layer portions are formed on opposite sides of the ITO upper cladding structure. The combination of ITO cladding and the SiO2 isolation structures provides a lateral index step that is large enough to enable lateral single-mode operation of the laser diode structure. In an alternative embodiment, the lateral index step is further increased by slightly etching the GaN:Mg waveguide layer below the SiO2 isolation layer portions.
In accordance with another embodiment of the present invention, an optional p-type current barrier layer (e.g., AlGaN:Mg having a thickness of approximately 20 nm) is formed between the InGaN-MQW region and a p-GaN upper waveguide layer to impede electron leakage from the InGaN-MQW region.
BRIEF DESCRIPTION OF THE DRAWINGS
These and other features, aspects and advantages of the present invention will become better understood with regard to the following description, appended claims, and accompanying drawings, where:
FIG. 1 is a perspective view showing an InGaN-based laser diode structure according to the present invention;
FIG. 2 is a graph relating the confinement factor and effective index to waveguide thickness in the InGaN-based laser diode structure shown in FIG. 1;
FIG. 3 is a perspective view showing a conventional InGaN-based laser diode structure; and
FIGS. 4(A) and 4(B) are graphs showing calculated confinement factors and metal absorption losses for a conventional InGaN-based laser diode structure.
DETAILED DESCRIPTION OF THE DRAWINGS
The present invention is described below with particular reference to InGaN-based laser diode structures. While the present invention is believed to be particularly useful in conjunction with InGaN-based laser diode structures, aspects of the present invention may be utilized in other nitride-based laser diode structures as well, and may also be utilized in some non-nitride-based laser diode structures (e.g., Gallium-Arsenide (GaAs) or Indium-Phosphate (InP) laser diode structures). For example, in an InP-based laser diode used as a chemical sensor, it may be useful to utilize a metal-oxide (e.g., ZnO) in the manner described herein because of its biocompatibility and sensitivity to hydrogen. Therefore, it is the intent of the inventors that the scope of the present invention not necessarily limited by the specific embodiments described herein unless such limitations are specifically included in the appended claims.
FIG. 1 is a front elevation view showing a nitride-based laser device structure 100 according to an embodiment of the present invention. Laser device structure 100 is formed on a substrate 101 (e.g., (, Sapphire Al2O3), Silicon-Carbide (SiC), Aluminum-Nitride (AlN), or Gallium-Nitride (GaN)), and includes a n-type contact layer 110 (e.g., GaN:Si or AlGaN:Si) formed on substrate 101. An n-electrode 120 (e.g., Ti/Au, Ti/Al, Ti/Al/Au, or Ti/Al/Mo/Au) is formed on a first (exposed) region of n-type contact layer 110, and an n-type lower cladding layer 13.0 (e.g., AlGaN:Si) is formed on a second region of N-type contact layer 110. An n-type lower waveguide layer 140 (e.g., GaN:Si, InGaN:Si, or AlGaN:Si) is formed on lower cladding layer 130. Note that the refractive index of lower waveguide layer 140 is larger than the refractive index of lower cladding layer 130. A multiple quantum well (MQW) region 150 (e.g., three InGaN quantum well layers sandwiched between corresponding GaN or InGaN barrier layers) is formed on lower waveguide layer 140. An optional p-type confinement layer 160 (e.g., AlGaN:Mg) is formed on MQW region 150. A p-type upper waveguide layer 170 (e.g., GaN:Mg, AlGaN:Mg or InGaN:Mg) is formed on confinement layer 160. An upper cladding layer 180 is formed on upper waveguide layer 170 and located over an active region 155 of MQW region 150. Optional isolation layer portions 185 are formed on opposite sides of upper cladding layer 180. Finally, a p-electrode 190 (e.g., Ti/Au, Ti/Al, Ti/Al/Au, Ti/Al/Mo/Au, Ni/Au, or Ni/Al) is formed on upper cladding layer 180 and isolation layer portions 185 (when used). The various Group III-nitride layers of laser device structure 100 that are shown in FIG. 1 and mentioned above are formed using metal organic chemical vapor deposition (MOCVD), which is a well known deposition technique (see, for example, “Organometallic Vapor-Phase Epitaxy: Theory and Practice”, G. B. Stringfellow, Academic Press, 1989).
According to an aspect of the present invention, upper cladding layer 180 is formed using a conductive metal-oxide selected from the group including Indium-Tin-Oxide (ITO), Zinc-Oxide (ZnO), Cadmium-Oxide (CdO), Indium-Oxide (In2O3), and Tin-Oxide (SnO2). Several ternary conductive metal oxides may also be used (e.g., Zn2SnO4, ZnSnO3, and Cd2NsO4). In addition, these oxides can be doped to increase their conductivity. For example, ZnO can be doped with Al, Ga, In, Fluorine (F), and/or Boron (B) to make the ZnO highly n-type (typical carrier concentrations-are approximately 1018 cm−3 to 2×1021 cm−3). It may also be possible to make these oxides p-type using similar doping techniques (e.g., nitrogen-doping might be used to create p-type ZnO). Note that ITO is another example of a doped oxide (the chemical formula of ITO is Zn2-xSnx 0 3). In the case of ITO, the Sn acts as the n-dopant in the In2O3 matrix. Conductive oxide layers can be deposited by continuous well-known deposition techniques. These techniques include sputtering (e.g., R. F. sputtering or R. F. magnetron sputtering), evaporation, or pulsed laser deposition. Chemical vapor deposition (CVD) is another method of depositing conductive metal films. Note that MOCVD is a CVD technique that facilitates the deposition of high quality crystalline films.
As set forth in the examples provided below, utilizing a metal-oxide material such as ITO to form upper cladding layer 180, particularly when combined with isolation layer portions 185 formed using a suitable dielectric material (e.g., SiO2), produces an nitride-based laser diode structure that has several advantages over conventional nitride-based laser diode structures formed with AlGaN:Mg upper cladding layers. For example, metal-oxides such as ITO and ZnO have a lower series resistance than AlGaN:Mg. Therefore, nitride-based laser device structure 100 avoid the heating problem associated with conventional nitride-based laser structures having upper cladding layers including AlGaN:Mg. Other advantages associated with the use of metal-oxide cladding structures are set forth below.
Referring again to FIG. 1, upper cladding layer 180 is formed into an elongated stripe (or ridge) structure having opposing side walls 180A and 180B (indicated by dashed lines) that extend substantially perpendicular to an upper surface of waveguide layer 170. The thus-formed upper cladding layer 180 defines the lateral index step and provides lateral single mode operation during lasing. This elongated structure is typically formed by depositing a continuous layer of cladding material, and then etching portions of the continuous layer to form the elongated structure having side walls 180A and 180B. As set forth above, in conventional nitride-based laser diode structures the upper cladding layer 180 typically includes AlGaN:Mg, which must be dry-etching to form a suitable ridge-waveguide structure because there is no reliable selective etch process known for AlGaN. Therefore, the etch depth and the resulting index step are difficult to control in conventional nitride-based laser diode structures using upper cladding layers formed using AlGaN:Mg. In contrast, metal-oxide can be selectively wet or dry etched using well-established techniques (e.g., wet etch using HCl or HF dilutes 10:1 with H2O; plasma dry etch in CF4O2 gas mixture), thereby providing a clear advantage over AlGaN:Mg cladding layers by avoiding over-etching that can undesirably alter the index step of the laser structure. This ability to selectively etch the cladding material simplifies the fabrication process, thereby reducing the manufacturing costs associated with producing nitride-based laser device structure 100. Further, as set forth below, the ability to selectively etch the cladding material is also important because the thickness of waveguide layer 170 is very important to the performance of nitride-based laser device structure 100.
As mentioned above, isolation layer portions 185 are formed on opposite sides of upper cladding layer 180 (see FIG. 1). In order to obtain lateral single mode operation, a lateral effective refractive index step is obtained by surrounding conductive oxide layer stripe 180 with a lower refractive index material (typical stripe width is between 1 to 4 microns). As set forth in additional detail below, this control function is particularly enhanced when upper cladding layer is formed using ITO and isolation layer portions 185 are formed using SiO2, but beneficial structures can also be formed using different electrically isolating dielectric materials having a lower refractive index (e.g., air, Si3N4, or SixOyNz). Dielectric isolation layer portions 185 also provide electric isolation between the wide p-electrode 190 and the underlying p-GaN waveguide layer 170, such that current is only funneled into the active region underneath metal-oxide cladding stripe 180.
According to another aspect of the present invention, optional tunnel barrier layer 160 (e.g., a layer of AlGaN:Mg having a thickness in the range of 5 to 50 nm, preferrably approximately 20 nm, for a GaN:Mg waveguide layer having a thickness in the range of 80 to 200 nm, preferably 120 nm) may be utilized in nitride-based laser diode structures to prevent leakage of electrons from of MQW region 150. In one embodiment, the Al content in tunnel barrier layer 160 is in the range of 10 to 30% (mole fraction). While tunnel barrier layer 160 having Al contents in this range may be necessary in some nitride-based laser diode structures in order to achieve lasing, it is possible to form nitride-based laser structures that do not require tunnel barrier layer 160. For example, U.S. Pat. Nos. 6,389,051 6,430,202, both entitled Structure and Method for Asymmetric Waveguide Nitride Laser Diode (incorporated herein by reference in their entirety) disclose an arrangement in which Al is added to upper waveguide layer 170 in an amount high enough to achieve the desired band gap offset. In one example, AlGaN:Mg lower waveguide layer 170 has an Al content of 8% (mole fraction) and has a thickness of 120 nm (i.e., similar to that used in the specific example provided below). The lower waveguide 140 in this example is GaN.
Referring again to FIG. 1, according to a specific embodiment, an AlGaN laser diode structure 100 is constructed according to the following specifications. Lower cladding layer 130 includes AlGaN:Si having a thickness of approximately 1,000 nm. Lower waveguide layer 140 includes GaN:Si having a thickness of approximately 100 nm. InGaN-MQW region 150 includes three InGaN quantum well layers having thicknesses in the range of 3 to 4 nm, with GaN layers in the range of 6 to 7 nm formed between the InGaN quantum well layers, and a 3 nm GaN capping layer. Barrier layer 160 is formed on the capping layer, and includes AlGaN:Mg having a thickness of approximately 20 nm. Upper waveguide layer 170 includes GaN:Mg having a thickness in the range of 50 to 200 nm, and most preferably approximately 120 nm for reasons described below. Upper cladding layer 180 includes ITO having a thickness in the range of 100 to 1000 nm (e.g., approximately 200 nm). Isolation layer portions 185 include SiO2, and have thicknesses that are greater than 100 nm (see alternative embodiment described below for exception). Finally, p-electrode 190 includes Ti/Au having a thickness of approximately 1020 nm (e.g., 20 nm Ti, 1000 nm Au).
The use of ITO to form upper cladding layer 180 is beneficial for several reasons. ITO has been shown to be highly conductive (ρ˜5*10−4 Ωcm) and forms a good ohmic contact to GaN:Mg (e.g., Margalith et. al, Appl. Phys. Lett. Vol 74, 3930 (1999)). Further, because ITO has a lower refractive index (nr=2.06@420 nm) than GaN (nr˜2.5), it provides a sufficiently large refractive index step to serve as upper cladding layer 180 in the laser diode structure. Although ITO is not completely transparent in the wavelength region around 400 nm (α˜700 cm−1@λ=420 nm), the calculated modal loss for laser diode 100, where cladding layer 180 and isolation layer 185 are 200 nm thick and are made up of ITO and SiO2, respectively, was found to be below 1 cm−1. This modal loss is much smaller than the distributed loss found in InGaAlN laser diodes, which is typically in the range of 20 cm−1 to 60 cm−1, and even lower than the loss found in conventional structures using AlGaN cladding layers.
As shown in Table 1 (below) and in FIG. 2, the total optical confinement factor Γ for the structure with ITO cladding layer 180 and a three-quantum-well active region 150 is around 3.6%. In particular, Table 1 shows calculated confinement factors and modal losses (from absorption in top metal and/or ITO) for a conventional InGaN laser diode structure having a 500 nm AlGaN:Mg upper cladding layer and InGaN laser diode structure 100 of the specific embodiment (set forth above). For the calculation of the modal loss, absorption in p-electrode 190 and in the ITO cladding layer (assuming an absorption coefficient of α˜700 cm−1 for ITO) were taken into account. All other layers in the laser structures were assumed to be loss-free. Note that the confinement factor for the ITO cladding structure is greater than the confinement factor for conventional devices with an AlGaN:Mg upper cladding layer (Γ˜3.0%), and should therefore result in enhanced modal gain and lower threshold current densities.
TABLE 1
Structure Γ α
500 nm AlGaN clad 1.01% per QW  1.6 cm−1
200 nm ITO clad 1.21% per QW 0.005 cm−1
Table 1 and FIG. 2 also indicate that the effective refractive index for the transverse optical mode guided underneath the SiO2 isolation layer portions 185 is smaller than the optical mode under the ITO cladding layer 180. The calculated lateral index step is about 0.005, which is sufficiently large to enable lateral single-mode operation. If necessary, the lateral index step can be further enhanced by slightly etching in the GaN:Mg waveguide layer 170 before deposition of the SiQ2 dielectric, or by using a different electrically isolating dielectric material with a lower refractive index (e.g., air). For example, by removing 20 nm of GaN:Mg from upper waveguide layer 170 in the area of the SiO2 isolation layer portions 185, the lateral index step can be increased to 0.012.
FIG. 2 also indicates that the confinement factor and effective index under the ITO cladding is maximized when waveguide layer 170 has a thickness of approximately 120 nm. However, as indicated, beneficial results can be achieved using waveguide thicknesses over the entire range disclosed in FIG. 2 (i.e., 50 to approximately 200 nm).
Although the present invention has been described with respect to certain specific embodiments, it will be clear to those skilled in the art that the inventive features of the present invention are applicable to other embodiments as well, all of which are intended to fall within the scope of the present invention.

Claims (19)

1. A laser diode structure comprising:
a quantum well region;
a waveguide layer formed over the quantum well region; and
a conductive metal-oxide cladding layer formed on the waveguide layer,
wherein the quantum well region comprises alternating layers of Indium-Gallium-Nitride and Gallium-Nitride, and
wherein the waveguide layer comprises Gallium-Nitride doped with Magnesium (GaN:Mg).
2. The laser diode structure according to claim 1, wherein the metal-oxide cladding layer comprises at least one of Indium-Tin-Oxide (ITO), Zinc-Oxide (ZnO), Cadmium-Oxide (edo), Tin-Oxide (SnO).
3. The laser diode structure according to claim 1,
wherein the waveguide layer comprises a thickness in the range of 50 to 200 nm, and
wherein the metal-oxide cladding layer comprises at least one of Indium-Tin-Oxide (ITO), Zinc-Oxide (ZnO), Cadmium-Oxide (CdO), Tin-Oxide (SnO).
4. The laser diode structure according to claim 3, wherein the metal-oxide cladding layer comprises ITO having a thickness in the range of 200 and 1000 nm.
5. A laser diode structure comprising:
a quantum well region;
a waveguide layer formed over the quantum well region; and
a conductive metal-oxide cladding layer formed on the waveguide layer,
wherein the metal-oxide cladding layer comprises first and second side walls extending perpendicular to an upper surface of the waveguide layer, and wherein the laser diode structure further comprising an isolation layer formed on the waveguide layer and including a first portion contacting the first side wall of the metal-oxide cladding layer, and a second portion contacting the second side wall of the metal-oxide cladding layer.
6. The laser diode structure according to claim 5, wherein the metal-oxide cladding layer comprises at least one of Indium-Tin-Oxide (ITO), Zinc-Oxide (ZnO), Cadmium-Oxide (CdO), Tin-Oxide (SnO), and wherein the isolation layer comprises one of Silicon-Oxide (SiO2), Silicon-Nitride (Si3N4), Silicon-Oxy-Nitride (SiON) and air.
7. The laser diode structure according to claim 5,
wherein the quantum well region comprises alternating layers of Indium-Gallium-Nitride and Gallium-Nitride,
wherein the waveguide layer comprises Gallium-Nitride doped with Magnesium (GaN:Mg) and having a thickness in the range of 50 to 200 nm, and
wherein the metal-oxide cladding layer comprises ITO having a thickness in the range of 100 to 1000 nm, and
wherein the isolation layer comprises SiO2 having a thickness in the range of 50 to 500 nm.
8. The laser diode structure according to claim 7, further comprising a metal electrode formed on an upper surface of the ITO cladding layer.
9. The laser diode structure according to claim 7, wherein a thickness of a first portion of the waveguide layer located under the metal-oxide cladding layer is in a range of approximately 5 nm to approximately 50 nm thicker than a second portion of the waveguide layer located under the isolation layer.
10. The laser diode structure according to claim 1, further comprising a current barrier layer formed between the quantum well region and the waveguide layer.
11. The laser diode structure according to claim 10,
wherein the current barrier layer comprises Aluminum-Gallium-Nitride doped with Magnesium (AlGaN:Mg) and having a thickness in the range of 5 to 50 nm,
wherein the waveguide layer comprises a thickness in the range of 50 to 200 nm, and
wherein the metal-oxide cladding layer comprises one of Indium-Tin-Oxide (ITO) and Zinc-Oxide (ZnO) having a thickness in the range of 100 to 1000 nm.
12. A method for fabricating a laser diode structure comprising:
forming a quantum well region;
forming a waveguide layer over the quantum well region; and
forming a conductive metal-oxide cladding layer on the waveguide layer,
wherein forming the quantum well region comprises forming alternating layers of Indium-Gallium-Nitride and Gallium-Nitride, and
wherein forming the waveguide layer comprises depositing Gallium-Nitride doped with Magnesium (GaN:Mg).
13. The method according to claim 12, wherein forming the metal-oxide cladding layer comprises depositing at least one of Indium-Tin-Oxide (ITO), Zinc-Oxide (ZnO), Cadmium-Oxide (CdO), Tin-Oxide (SnO).
14. The method according to claim 12, wherein forming the metal-oxide cladding layer comprises depositing ITO to a thickness in the range of 100 to 1000 nm.
15. The method according to claim 12, wherein forming the metal-oxide cladding layer comprises depositing an Indium-Tin-Oxide (ITO) layer, and then etching portions of the ITO layer to form an ITO structure having side walls extending perpendicular to an upper surface of the waveguide layer.
16. The method according to claim 15, further comprising forming an isolation layer on the waveguide layer adjacent to the ITO structure such that the isolation layer includes a first portion contacting the first side wall of the ITO structure, and a second portion contacting the second side wall of the ITO structure.
17. The method according to claim 16, wherein forming the isolation layer comprises depositing Silicon-Oxide (SiO2).
18. The method according to claim 17, wherein forming the waveguide layer comprises etching portions of the waveguide layer such that the SiO2 is deposited on the etched portions.
19. The method according to claim 17, wherein the etched portions have a thickness in the range of 50 to 100 nm.
US10/394,560 2003-03-20 2003-03-20 Laser diode with metal-oxide upper cladding layer Active 2024-04-06 US6990132B2 (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
US10/394,560 US6990132B2 (en) 2003-03-20 2003-03-20 Laser diode with metal-oxide upper cladding layer

Applications Claiming Priority (3)

Application Number Priority Date Filing Date Title
US10/394,560 US6990132B2 (en) 2003-03-20 2003-03-20 Laser diode with metal-oxide upper cladding layer
EP04251338A EP1460741A1 (en) 2003-03-20 2004-03-09 Laser diode
JP2004079581A JP2004289157A (en) 2003-03-20 2004-03-19 Laser diode structure and manufacturing method thereof

Publications (2)

Publication Number Publication Date
US20040184497A1 US20040184497A1 (en) 2004-09-23
US6990132B2 true US6990132B2 (en) 2006-01-24

Family

ID=32824926

Family Applications (1)

Application Number Title Priority Date Filing Date
US10/394,560 Active 2024-04-06 US6990132B2 (en) 2003-03-20 2003-03-20 Laser diode with metal-oxide upper cladding layer

Country Status (3)

Country Link
US (1) US6990132B2 (en)
EP (1) EP1460741A1 (en)
JP (1) JP2004289157A (en)

Cited By (14)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20060003188A1 (en) * 2003-01-24 2006-01-05 Bridgestone Corporation ITO thin film, method of producing the same, transparent conductive film, and touch panel
US20070098030A1 (en) * 2005-11-03 2007-05-03 Samsung Electronics Co., Ltd. Nitride semiconductor laser device and method of manufacturing the same
US20110291140A1 (en) * 2010-05-27 2011-12-01 Choi Kwang Ki Light emitting device and light emitting device package
US20120199863A1 (en) * 2009-06-25 2012-08-09 Koninklijke Philips Electronics N.V. Contact for a semiconductor light emitting device
US20130299846A1 (en) * 2012-05-09 2013-11-14 Nxp B.V Group 13 nitride semiconductor device and method of its manufacture
US20140138621A1 (en) * 2003-07-18 2014-05-22 Lg Innotek Co., Ltd. Gallium nitride based light emitting diode and fabrication method thereof
US8942269B2 (en) 2011-03-24 2015-01-27 Panasonic Corporation Nitride semiconductor light-emitting device
US9472741B2 (en) 2012-04-16 2016-10-18 Panasonic Intellectual Property Management Co., Ltd. Semiconductor light-emitting device
US9583353B2 (en) 2012-06-28 2017-02-28 Yale University Lateral electrochemical etching of III-nitride materials for microfabrication
US10458038B2 (en) 2010-01-27 2019-10-29 Yale University Conductivity based on selective etch for GaN devices and applications thereof
US10554017B2 (en) 2015-05-19 2020-02-04 Yale University Method and device concerning III-nitride edge emitting laser diode of high confinement factor with lattice matched cladding layer
US11018231B2 (en) 2014-12-01 2021-05-25 Yale University Method to make buried, highly conductive p-type III-nitride layers
US11043792B2 (en) 2014-09-30 2021-06-22 Yale University Method for GaN vertical microcavity surface emitting laser (VCSEL)
US11095096B2 (en) 2014-04-16 2021-08-17 Yale University Method for a GaN vertical microcavity surface emitting laser (VCSEL)

Families Citing this family (32)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US7279751B2 (en) * 2004-06-21 2007-10-09 Matsushita Electric Industrial Co., Ltd. Semiconductor laser device and manufacturing method thereof
JP4909533B2 (en) * 2004-06-21 2012-04-04 パナソニック株式会社 Semiconductor laser device and manufacturing method thereof
KR100590562B1 (en) 2004-10-27 2006-06-19 삼성전자주식회사 Semiconductor Laser Diode with Multi Quantum Barrier Clad Layers
US7751455B2 (en) * 2004-12-14 2010-07-06 Palo Alto Research Center Incorporated Blue and green laser diodes with gallium nitride or indium gallium nitride cladding laser structure
US7885306B2 (en) * 2006-06-30 2011-02-08 Osram Opto Semiconductors Gmbh Edge-emitting semiconductor laser chip
DE102006060410A1 (en) * 2006-06-30 2008-01-03 Osram Opto Semiconductors Gmbh Edge-emitting semiconductor laser chip
JP2008235606A (en) * 2007-03-20 2008-10-02 Sony Corp Semiconductor light-emitting element, method for manufacturing semiconductor light-emitting element, backlight, display unit, electronic equipment, and light-emitting device
WO2008130223A1 (en) * 2007-04-20 2008-10-30 Technische Universiteit Eindhoven Laser diode element
JP2009094360A (en) * 2007-10-10 2009-04-30 Rohm Co Ltd Semiconductor laser diode
EP2059039A1 (en) 2007-10-31 2009-05-13 Thomson Licensing Global anticamcorder projection system and method
EP2224558B1 (en) * 2007-11-08 2017-08-16 Nichia Corporation Semiconductor laser element
JP5444609B2 (en) * 2007-11-08 2014-03-19 日亜化学工業株式会社 Semiconductor laser element
TWI381547B (en) * 2007-11-14 2013-01-01 Advanced Optoelectronic Tech Light emitting device of iii-nitride based semiconductor and manufacturing method thereof
US7928448B2 (en) 2007-12-04 2011-04-19 Philips Lumileds Lighting Company, Llc III-nitride light emitting device including porous semiconductor layer
KR20100098565A (en) * 2007-12-19 2010-09-07 로무 가부시키가이샤 Semiconductor light-emitting device
US20110133175A1 (en) * 2008-01-08 2011-06-09 Yungryel Ryu High-performance heterostructure light emitting devices and methods
JP2010016261A (en) * 2008-07-04 2010-01-21 Sharp Corp Nitride semiconductor laser element
JP5223531B2 (en) * 2008-08-06 2013-06-26 日亜化学工業株式会社 Semiconductor laser element
US7856040B2 (en) * 2008-09-24 2010-12-21 Palo Alto Research Center Incorporated Semiconductor light emitting devices with non-epitaxial upper cladding
CN101807634B (en) * 2009-02-17 2012-04-04 罗信明 High-brightness light emitting diode chip
DE102010040767B4 (en) * 2010-09-14 2014-01-30 Forschungsverbund Berlin E.V. Laser diode with high efficiency and high eye safety
DE102010046793A1 (en) * 2010-09-28 2012-03-29 Osram Opto Semiconductors Gmbh Edge-emitting semiconductor laser diode and method for its production
JP2013042107A (en) * 2011-02-17 2013-02-28 Rohm Co Ltd Semiconductor laser element
US8354689B2 (en) 2011-04-28 2013-01-15 Palo Alto Research Center Incorporated Light emitting devices having dopant front loaded tunnel barrier layers
JP2013102043A (en) * 2011-11-08 2013-05-23 Sumitomo Electric Ind Ltd Semiconductor laser element and semiconductor laser element manufacturing method
DE102012220911A1 (en) * 2012-09-27 2014-05-15 Osram Opto Semiconductors Gmbh Semiconductor laser with improved current conduction
DE102015116335A1 (en) * 2015-09-28 2017-03-30 Osram Opto Semiconductors Gmbh Semiconductor laser
JPWO2018083896A1 (en) 2016-11-01 2019-09-19 ソニーセミコンダクタソリューションズ株式会社 Semiconductor device, semiconductor laser, and manufacturing method of semiconductor device
DE102017113389B4 (en) * 2017-06-19 2021-07-29 OSRAM Opto Semiconductors Gesellschaft mit beschränkter Haftung Semiconductor laser diode
JP2020527857A (en) * 2017-07-14 2020-09-10 キング・アブドゥッラー・ユニバーシティ・オブ・サイエンス・アンド・テクノロジー Nitride-based electronic device with oxide clad layer and manufacturing method
CN107507891B (en) * 2017-08-10 2019-02-15 湘能华磊光电股份有限公司 Improve the LED epitaxial growth method of internal quantum efficiency
DE112019000483T5 (en) * 2018-01-23 2020-10-29 Sony Semiconductor Solutions Corporation SEMICONDUCTOR LASER AND ELECTRONIC DEVICE

Citations (14)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5493577A (en) * 1994-12-21 1996-02-20 Sandia Corporation Efficient semiconductor light-emitting device and method
WO1998007218A1 (en) 1996-08-09 1998-02-19 W.L. Gore & Associates, Inc. Vertical cavity surface emitting laser with tunnel junction
US5726462A (en) 1996-02-07 1998-03-10 Sandia Corporation Semiconductor structures having electrically insulating and conducting portions formed from an AlSb-alloy layer
US6174747B1 (en) 1998-12-23 2001-01-16 Industrial Technology Research Institute Method of fabricating ridge waveguide semiconductor light-emitting device
US6189340B1 (en) * 1996-06-17 2001-02-20 Corning Incorporated Process for forming a titania-containing preform silica glass blank
US6233265B1 (en) 1998-07-31 2001-05-15 Xerox Corporation AlGaInN LED and laser diode structures for pure blue or green emission
US6327413B1 (en) * 1998-02-02 2001-12-04 Kabushiki Kaisha Toshiba Optoelectronic device and laser diode
WO2001093387A2 (en) 2000-05-31 2001-12-06 Sandia Corporation Long wavelength vertical cavity surface emitting laser
FR2815773A1 (en) 2000-10-23 2002-04-26 X Ion Production of an ultra thin oxide grid layer on a semiconductor substrate using an interface layer and an integrating layer with minimal thickness
US6389051B1 (en) 1999-04-09 2002-05-14 Xerox Corporation Structure and method for asymmetric waveguide nitride laser diode
US6430202B1 (en) 1999-04-09 2002-08-06 Xerox Corporation Structure and method for asymmetric waveguide nitride laser diode
US6479836B1 (en) * 1999-08-19 2002-11-12 Kabushiki Kaisha Toshiba Semiconductor light emitting device
US20030026515A1 (en) 2001-08-01 2003-02-06 Motorola, Inc. Monolithic tunable wavelength multiplexers and demultiplexers and methods for fabricating same
US6693352B1 (en) * 2000-06-05 2004-02-17 Emitronix Inc. Contact structure for group III-V semiconductor devices and method of producing the same

Family Cites Families (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2885198B2 (en) * 1996-09-18 1999-04-19 日本電気株式会社 P-type electrode structure and semiconductor light emitting device having the same
JP3521186B2 (en) * 1999-09-01 2004-04-19 日本電信電話株式会社 Nitride semiconductor optical device and method of manufacturing the same
JP2002016285A (en) * 2000-06-27 2002-01-18 National Institute Of Advanced Industrial & Technology Semiconductor light-emitting element

Patent Citations (14)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5493577A (en) * 1994-12-21 1996-02-20 Sandia Corporation Efficient semiconductor light-emitting device and method
US5726462A (en) 1996-02-07 1998-03-10 Sandia Corporation Semiconductor structures having electrically insulating and conducting portions formed from an AlSb-alloy layer
US6189340B1 (en) * 1996-06-17 2001-02-20 Corning Incorporated Process for forming a titania-containing preform silica glass blank
WO1998007218A1 (en) 1996-08-09 1998-02-19 W.L. Gore & Associates, Inc. Vertical cavity surface emitting laser with tunnel junction
US6327413B1 (en) * 1998-02-02 2001-12-04 Kabushiki Kaisha Toshiba Optoelectronic device and laser diode
US6233265B1 (en) 1998-07-31 2001-05-15 Xerox Corporation AlGaInN LED and laser diode structures for pure blue or green emission
US6174747B1 (en) 1998-12-23 2001-01-16 Industrial Technology Research Institute Method of fabricating ridge waveguide semiconductor light-emitting device
US6430202B1 (en) 1999-04-09 2002-08-06 Xerox Corporation Structure and method for asymmetric waveguide nitride laser diode
US6389051B1 (en) 1999-04-09 2002-05-14 Xerox Corporation Structure and method for asymmetric waveguide nitride laser diode
US6479836B1 (en) * 1999-08-19 2002-11-12 Kabushiki Kaisha Toshiba Semiconductor light emitting device
WO2001093387A2 (en) 2000-05-31 2001-12-06 Sandia Corporation Long wavelength vertical cavity surface emitting laser
US6693352B1 (en) * 2000-06-05 2004-02-17 Emitronix Inc. Contact structure for group III-V semiconductor devices and method of producing the same
FR2815773A1 (en) 2000-10-23 2002-04-26 X Ion Production of an ultra thin oxide grid layer on a semiconductor substrate using an interface layer and an integrating layer with minimal thickness
US20030026515A1 (en) 2001-08-01 2003-02-06 Motorola, Inc. Monolithic tunable wavelength multiplexers and demultiplexers and methods for fabricating same

Cited By (17)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20060003188A1 (en) * 2003-01-24 2006-01-05 Bridgestone Corporation ITO thin film, method of producing the same, transparent conductive film, and touch panel
US8927960B2 (en) * 2003-07-18 2015-01-06 Lg Innotek Co., Ltd. Gallium nitride based light emitting diode
US9362454B2 (en) 2003-07-18 2016-06-07 Lg Innotek Co., Ltd. Gallium nitride based light emitting diode
US20140138621A1 (en) * 2003-07-18 2014-05-22 Lg Innotek Co., Ltd. Gallium nitride based light emitting diode and fabrication method thereof
US20070098030A1 (en) * 2005-11-03 2007-05-03 Samsung Electronics Co., Ltd. Nitride semiconductor laser device and method of manufacturing the same
US20120199863A1 (en) * 2009-06-25 2012-08-09 Koninklijke Philips Electronics N.V. Contact for a semiconductor light emitting device
US10458038B2 (en) 2010-01-27 2019-10-29 Yale University Conductivity based on selective etch for GaN devices and applications thereof
US20110291140A1 (en) * 2010-05-27 2011-12-01 Choi Kwang Ki Light emitting device and light emitting device package
US8942269B2 (en) 2011-03-24 2015-01-27 Panasonic Corporation Nitride semiconductor light-emitting device
US9472741B2 (en) 2012-04-16 2016-10-18 Panasonic Intellectual Property Management Co., Ltd. Semiconductor light-emitting device
US20130299846A1 (en) * 2012-05-09 2013-11-14 Nxp B.V Group 13 nitride semiconductor device and method of its manufacture
US9147732B2 (en) * 2012-05-09 2015-09-29 Nxp B.V. Group 13 nitride semiconductor device and method of its manufacture
US9583353B2 (en) 2012-06-28 2017-02-28 Yale University Lateral electrochemical etching of III-nitride materials for microfabrication
US11095096B2 (en) 2014-04-16 2021-08-17 Yale University Method for a GaN vertical microcavity surface emitting laser (VCSEL)
US11043792B2 (en) 2014-09-30 2021-06-22 Yale University Method for GaN vertical microcavity surface emitting laser (VCSEL)
US11018231B2 (en) 2014-12-01 2021-05-25 Yale University Method to make buried, highly conductive p-type III-nitride layers
US10554017B2 (en) 2015-05-19 2020-02-04 Yale University Method and device concerning III-nitride edge emitting laser diode of high confinement factor with lattice matched cladding layer

Also Published As

Publication number Publication date
US20040184497A1 (en) 2004-09-23
JP2004289157A (en) 2004-10-14
EP1460741A1 (en) 2004-09-22

Similar Documents

Publication Publication Date Title
US6990132B2 (en) Laser diode with metal-oxide upper cladding layer
JP3897186B2 (en) Compound semiconductor laser
EP1328050B1 (en) Semiconductor laser structure
US7756177B2 (en) Semiconductor light-emitting device
EP1328025B1 (en) Semiconductor laser structure
US20050040384A1 (en) Semiconductor light-emitting element and method of manufacturing the same
JP4902682B2 (en) Nitride semiconductor laser
US7123637B2 (en) Nitride-based laser diode with GaN waveguide/cladding layer
JP2013038394A (en) Semiconductor laser element
JP2007235107A (en) Semiconductor light-emitting device
KR20100098565A (en) Semiconductor light-emitting device
US20060093003A1 (en) Semiconductor laser device and process for preparing the same
JP3786907B2 (en) Semiconductor light emitting device and manufacturing method thereof
JP2003086903A (en) Semiconductor light emitting device and its manufacturing method
JP5717640B2 (en) Optoelectronic semiconductor chip and method of manufacturing optoelectronic semiconductor chip
JP4698181B2 (en) Nitride semiconductor laser device
JP2005260109A (en) Optical semiconductor element
JP2003060319A (en) Nitride semiconductor laser
JP2005327907A (en) Semiconductor laser element
JP4497606B2 (en) Semiconductor laser device
JP2006339311A (en) Semiconductor laser
JP3950473B2 (en) Compound semiconductor laser
WO2016157739A1 (en) Semiconductor light-emitting element
JP2007043215A (en) Compound semiconductor laser
JP2003023218A (en) Semiconductor laser element

Legal Events

Date Code Title Description
AS Assignment

Owner name: XEROX CORPORATION, CONNECTICUT

Free format text: ASSIGNMENT OF ASSIGNORS INTEREST;ASSIGNORS:KNEISSL, MICHAEL A.;ROMANO, LINDA T.;VAN DE WALLE, CHRISTIAN G.;REEL/FRAME:013899/0737;SIGNING DATES FROM 20030307 TO 20030318

AS Assignment

Owner name: JPMORGAN CHASE BANK, AS COLLATERAL AGENT, TEXAS

Free format text: SECURITY AGREEMENT;ASSIGNOR:XEROX CORPORATION;REEL/FRAME:015134/0476

Effective date: 20030625

Owner name: JPMORGAN CHASE BANK, AS COLLATERAL AGENT,TEXAS

Free format text: SECURITY AGREEMENT;ASSIGNOR:XEROX CORPORATION;REEL/FRAME:015134/0476

Effective date: 20030625

STCF Information on status: patent grant

Free format text: PATENTED CASE

CC Certificate of correction
AS Assignment

Owner name: DARPA, VIRGINIA

Free format text: CONFIRMATORY LICENSE;ASSIGNOR:XEROX CORPORATION;REEL/FRAME:017982/0349

Effective date: 20060606

FPAY Fee payment

Year of fee payment: 4

FPAY Fee payment

Year of fee payment: 8

FPAY Fee payment

Year of fee payment: 12